Experiments were concerned with the initial ocular following responses to transient ramp movements of the visual scene in monkeys and humans. These tracking movements are important in the stabilization of gaze which is so necessary for good visual acuity. We had previously shown in monkeys that responses have very short latency (approximately 50 msec) and are transiently enhanced following saccadic eye movements. We have now found that this enhancement results from the visual stimulation elicited by the saccade sweeping the retina across the visual scene. When no such visual stimulation is produced, as when a vertical saccade is made while viewing vertical stripes, for example, then no enhancement results: saccadic eye movements per se are not sufficient to elicit the enhancement. Furthermore, the enhancement could be evoked in the absence of saccades by shifting the visual scene in a manner that mimicked the visual events occurring during saccades: the visual stimulation received during saccadic eye movements is entirely responsible for the transient post-saccadic enhancement of ocular following. Using sine wave grating patterns of various spatial frequencies (0.05-l cycles/degree) drifting at various velocities (5-400 degrees/sec) to elicit ocular following revealed that the response latency was solely determined by the temporal frequency. This suggests that ocular following responses are triggered by local changes in luminance rather than movements of the overall pattern. Attempts to demonstrate inter-ocular transfer of enhancement were not successful: An optical arrangement that allowed the visual scene to sweep across one eye only during saccades did not enhance the ocular following responses elicited by movements seen only by the other eye. This is consistent with the view that the visual enhancement of ocular following is due to changes that occur in the visual system at an early stage in processing before information from the two eyes converges.